Insufficient exposure to light in the winter may result in a longer production periods and lower quality of seedlings in greenhouses for plug growers. Supplementary artificial lighting to plug seedlings may be one solution to this problem. The objective of this study was to assess the effects of the duration of the supplementary light on the growth and development of two watermelon cultivars, ‘Speed’ and ‘Sambok Honey’ grafted onto ‘RS-Dongjanggun’ bottle gourd rootstocks (Lagenaria siceraria Stanld). Seedlings were grown for 10 days in a glasshouse with an average daily natural light intensity of 340 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and daily supplementary lighting of 8, 12 or 16 h from mixed LEDs (W1R2B1, chip ratio of white:red:blue = 1:2:1) at a light intensity of 100 μmol·m−2·s−1 PPFD, a group without supplementary light was set as the control (CK). The culture environment in a glasshouse had 25/15 °C day/night temperatures, an 85 ± 5% relative humidity, and a natural photoperiod of 8 h. The results showed that all the growth and development parameters of seedlings grown with supplementary light were significantly greater than those without supplementary light (CK). The 12 and 16 h supplementary light resulted in greater growth and development parameters than the 8 h supplementary light did. The same trend was also found with the indexes that reflect the quality of the seedlings, such as the dry weight ratio of the shoot and root, total biomass, dry weight to height ratio of scions, and specific leaf weight. The 12 h and 16 h light supplements resulted in greater Dickson’s quality indexes compared to the 8 h supplementary light, and the 12 h supplementary light showed the greatest use efficiency of the supplementary light. 16 h of daily supplementary light significantly increased the H2O2 content and the antioxidant enzyme activities in seedlings compared to the other treatments. This indicated that 16 h of supplementary light led to certain stresses in watermelon seedlings. In conclusion, considering the energy consumption, 12 h of supplementary light was the most efficient in improving the quality of the two cultivars of grafted watermelon plug seedlings.

https://www.mdpi.com/2073-4395/10/3/337/pdf

Effect of Supplementary Lighting Duration on Growth and Activity of Antioxidant Enzymes in Grafted Watermelon Seedlings

Plant quality and survival prediction tools are useful when applied in the field in different agricultural sectors. The objectives of this study were to conduct a review and bibliometric analysis of the Dickson Quality Index (DQI) as a key plant quality indicator and with respect to its scientific applications. A third objective was to identify the main morphological and physiological parameters used in plant production research. The methodology and findings of 289 scientific articles were analysed based on the morphological, physiological, and mathematical parameters used as plant quality indicators in research on forest, medicinal, horticultural, aromatic, and ornamental species. During the last 10 years, the number of publications that have used the DQI as a plant quality parameter has increased by 150%, and Brazilian researchers stand out as the most frequent users. Forestry is the discipline where quality parameters and their biometric relationships are most often used to facilitate intensive plant production. Use of the DQI increases the certainty of prediction, selection, and productivity in the plant production chain. The DQI is a robust tool with scientific application and great potential for use in the preselection of plants with high quality standards among a wide range of plant species.

Plant Agronomic Features Can Predict Quality and Field Performance: A Bibliometric Analysis

Bu calismada farkli ortamlarda yetistirilen tutun fidelerinin tutunun gelisimi ve besin elementi iceriklerine etkisini incelemek amaclanmistir. Bu nedenle arastirma iki asamali olarak yurutulmustur. Birinci asamada farkli fide ortamlarinin( ahir gubresi, kompost, torf ve vermikompost) toprak ile olan 1/1 (hacim/hacim) karisimindan olusan ortamlarda tutun fideleri yetistirilmistir. Ikinci asamada ise bu fideler sera kosullarinda 4 kg toprak alan saksilara aktarilarak 3 ay sureyle gelisime birakilmistir. Elde edilen sonuclar, fide gelisimi ve fidelerin mineral beslenme durumlarinin, ortamlarinin ozelligine gore degistigi gorulurken; fide ortami ve fide ozelliklerinin de asil bitkinin verim ve mineral beslenmesini etkiledigi saptanmistir. Elde edilen sonuclar en iyi fide ortaminin ahir gubresi + toprak karisimi oldugunu gostermistir.

/pdf/effect-of-seedlings-obtained-from-different-growing-media-on-kp5uc12jc7.pdf

Effect of seedlings obtained from different growing media on tobacco growth and mineral nutrition

A difficulty in the production of tomato seedlings in containers is to assure the production of shoot biomass with limited portion of roots, restricted to a small volume of substrate. Therefore, we investigated if substrates associated with tomato cultivars interfere in the seedling quality. In this study, the treatments used were two tomato cultivars and three substrates. The experiment was designed in randomized blocks, with treatments arranged in a two-factorial scheme (2 x 3), with four replications. We carried out the physical and chemical characterization of the substrates and evaluated the attributes of the shoot and the root system of tomato seedlings. The results showed that the substrate with the highest water retention was Horta 2® and the lightest material was TN Gold®. Still, seedlings produced on the substrate with greater water retention capacity had higher performance in relation to the shoot morphology and the root system morphology. We conclude that the seedling quality of tomato cultivars is not associated with the studied substrates and that seedlings produced in substrate with greater water retention have better quality.

/pdf/quality-of-tomato-seedlings-produced-in-substrates-56xyr676bi.pdf

Quality of tomato seedlings produced in substrates

Adenium obesum (Forssk.) Roem. & Schult., widely known as desert rose, has attracted interest for its esthetic characteristics, which are influenced by the process of seedling production. Using two consecutive experiments installed fully at random, the study aimed at assessing the use of different substrates and hydrogel to produce desert rose seedlings in a protected environment. First, eleven substrates were tested, prepared as follows: OrganoAmazon®; PuroHumus®; soil; rice husk in natura; carbonized rice husk, sawdust and cattle manure. Then, three substrates were tested (S1 - OrganoAmazon® + PuroHumus®; S2 - OrganoAmazon® + PuroHumus® + rice husk in natura and S3 - OrganoAmazon® + PuroHumus® + carbonized rice husk) associated to four hydrogel levels: 0 (daily irrigation), 1, 2 and 3 g L-1 (irrigated on alternate days). Growth variables and quality index of seedlings were assessed. Six substrates (all of them without addition of sawdust and where used in mix) were grouped as those the promoted appropriate growth of seedlings, with height, number of leaves, collar diameter, root length and aerial part biomass superior to 6.5 cm; 13; 12 mm; 7.5 cm and 0.45 g, respectively. The substrate composed of OrganoAmazon® + PuroHumus® (1:1 v/v), when irrigated daily, was the one that favored most the production of quality seedlings. The use of hydrogel in substrates with shifts of irrigation on alternate days did not favor the production of desert rose seedlings.

/pdf/use-of-substrates-and-hydrogel-to-produce-desert-rose-12hf00ay7u.pdf

Use of substrates and hydrogel to produce desert rose seedlings.

The type of environment and substrates quality in seedlings production are essential for the production of productive plants under field conditions. In order to determine the best environment and substrate for seedlings production of two tomato cultivars (IPA 06 and Santamelia), two experiments, completely randomized and arranged in subdivided plots with five replicates, were conducted under the environmental conditions of Boa Vista, Roraima, Brazil. Treatments consisted of the association among five environments (A1 - greenhouse, A2 - Chromatinet ® 35% red, A3 - Chromatinet ® 50% red, A4 - Chromatinet ® 35% Silver and A5 - Chromatinet ® 50% Silver) and four substrates S1 - OrganAmazon®; S2 - OrganAmazon® + PureHumus®; S3 - OrganAmazon® + PureHumus® + soil + bovine manure, and S4- OrganAmazon® + PureHumus® + soil + manure + carbonized rice husk (CRH) on the following variables: number of leaves, plant height, stem diameter, dry shoot and root biomass, plant height/stem diameter ratio accordingly to colon & Dickson quality index of seedlings. Substrates made with the addition of PureHumus®, without presenting CRH (S2 and S3), which favored the increasing of all analyzed variables. In addition, greenhouse, especially when is associated to S2 substrate, had achieved the best environment for seedlings production of the two evaluated tomato cultivars. Photoconverter shading nets were not efficient in tomato seedlings production under climatic conditions of Boa Vista, Roraima, Brazil.

http://www.scielo.org.co/pdf/acag/v67n2/0120-2812-acag-67-02-00270.pdf

Raphael Henrique da Silva-Siqueira

Papers

Seedlings production of two tomato (Solanum licopersicum L.) cultivars under different environments and substrates